At present, form of tablet computers, and particularly their interface design, have become increasingly simple. For a tablet computer, data communication interface, charging interface, audio/video interface or even interface for vehicular equipments are integrated into one single physical interface, which is typically a micro Universal Serial Bus (USB) interface or a mini USB interface. However, at present, various types of cables including an adapter charging cable, a USB charging cable, an A-type USB cable, a B-type USB cable, an audio cable, a video cable or a cable for vehicular equipments, can be connected to the micro USB or mini USB interface of the tablet computer, only when an external expanding equipment, such as an expanding slot or an expanding base, is connected to the micro USB or mini USB interface. However, this not only increases user expenditure, but also results in great inconvenience due to the fact that when a user takes a tablet computer out, he/she has to carry the expanding equipment.